Patent Application
20160349016
Various constructions of multi-layer ballistic-resistant articles are known for use in garments, helmets, shields, and the like. Although such constructions may achieve acceptable levels of resistance to projectile penetration, there may also be other ballistic performance criteria. For example, upon a projectile striking an article, the article may deform such that the back face of the article impinges into the body region that the article is intended to protect. Thus, there may be performance criteria related to the amount of impingement into the body region.
A ballistic resistant article according to an example of the present disclosure includes a front strike face and a backing that is bound by stitching to the front strike face. The front strike face includes a rigid layer and the backing including at least one non-rigid fibrous layer.
In a further embodiment of any of the foregoing embodiments, the front strike face includes a layer of fibers disposed in a polymer matrix.
In a further embodiment of any of the foregoing embodiments, the front strike face is non-fibrous.
In a further embodiment of any of the foregoing embodiments, the front strike face includes aramid fibers.
In a further embodiment of any of the foregoing embodiments, the at least one non-rigid fibrous layer includes aramid fibers.
In a further embodiment of any of the foregoing embodiments, the at least one non-rigid fibrous layer includes unidirectional fibers.
In a further embodiment of any of the foregoing embodiments, the at least one non-rigid layer includes a woven fabric.
In a further embodiment of any of the foregoing embodiments, the front strike face and the backing have a combined weight, and the front strike face is 1% to 20% of the combined weight.
In a further embodiment of any of the foregoing embodiments, the rigid layer has at least two times the rigidity of the at least one non-rigid fibrous layer.
In a further embodiment of any of the foregoing embodiments, the at least one non-rigid fibrous layer includes a plurality of fibrous layers, and the fibrous layers are bound to each other and to the rigid layer exclusively by the stitching.
A ballistic resistant article according to an example of the present disclosure includes a rigid front strike face and a flexible backing that is loosely bound to the rigid front strike face. The rigid front strike face includes a layer of fibers disposed in a polymer matrix and the flexible backing includes a plurality of fabric layers. The rigid front strike face and the flexible backing have a combined weight, and the rigid front strike face is 1% to 20% of the combined weight.
In a further embodiment of any of the foregoing embodiments, the rigid front strike face is 1% to 10% of the combined weight.
In a further embodiment of any of the foregoing embodiments, the rigid front strike face is 5% to 10% of the combined weight.
In a further embodiment of any of the foregoing embodiments, the layer of fibers is of aramid fibers.
In a further embodiment of any of the foregoing embodiments, the fabric layers are of aramid fibers.
In a further embodiment of any of the foregoing embodiments, the flexible backing is loosely bound by stitching to the rigid front strike face.
In a further embodiment of any of the foregoing embodiments, the fabric layers are free of any matrix material.
A ballistic resistant article according to an example of the present disclosure includes a rigid front strike face and a flexible backing that is bound by stitching to the rigid front strike face. The rigid front strike face consists of a layer of fibers disposed in a polymer matrix and the flexible backing consists of a plurality of fabric layers. The fabric layers are bound to each other and to the rigid front strike face substantially exclusively by the stitching. The rigid front strike face and the flexible backing have a combined weight, and 1% to 10% of the combined weight is the rigid front strike face.
In a further embodiment of any of the foregoing embodiments, the layer of fibers and the fabric layers are each of aramid fibers, and the fabric layers are free of any matrix material.
The various features and advantages of the present disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
In the illustrated example, the article 20 includes a front strike face 22 and a backing 24 that is bound by stitching 26 to the front strike face 22. The terms “front,” “back,” “rear,” and variations thereof refer to the orientation of the article 20 relative to a projectile threat, represented at T, and a body region, represented at R. For example, the body region R is the region which the article 20 protects.
The front strike face 22 includes a rigid layer 22a. For example, the rigid layer 22a has an exposed front surface, FS, and a rear surface, RS. The rear surface is adjacent the backing 24. The backing 24 includes at least one non-rigid fibrous layer, represented at 28. The non-rigid fibrous layer 28 is non-rigid relative to the rigid layer 22a and may also be considered to be a flexible layer. In one example, the rigid layer 22a is at least two times more rigid than the non-rigid fibrous layer 28. In this example, the backing 24 is depicted with four such layers 28a/28b/28c/28d. In further examples, the backing 24 can include from one such layer up to approximately fifty such layers.
In a further example, the non-rigid fibrous layers 28 of the backing 24 are loosely bound to each other and to the rigid layer 22a. For instance, the non-rigid fibrous layers 28 and the rigid layer 22a can move relative to one another, such as on impact from a projectile. In the illustrated example, the stitching 26 can loosely bound the non-rigid fibrous layers 28 to each other and to the rigid layer 22a.
In another example, the non-rigid fibrous layers 28 of the backing 24 are bound to each other and to the rigid layer 22a exclusively by the stitching 26. In yet a further example, the non-rigid fibrous layers 28 of the backing 24 are bound to each other and to the rigid layer 22a substantially exclusively by the stitching 26. For instance, one or more of the non-rigid fibrous layers 28 and the rigid layer 22a may include a binder, adhesive, or the like, which may contribute to bounding the non-rigid fibrous layers 28 to each other and/or to the rigid layer 22a. However, the contribution to the bound-together strength of any binder, adhesive, or other substance is less than the contribution of the stitching 26.
Upon the projectile threat T striking the article 20, the projectile threat initially impacts the rigid layer 22a. The rigid layer 22a may not be constructed to resist penetration. The projectile threat T passes through the rigid layer 22a to the backing 24. The backing 24 resists penetration but, because the layers 28a/28b/28c/28d are non-rigid, the layers 28a/28b/28c/28d tend to deform in the direction of the threat impact into the body region R, as represented at 28a′/28b′/28c′/28d′. The configuration of the article 20 limits impingement into the body region R. The impact of the threat to the backing 24 is transferred, at least in part, by stitching 26 or bounding, as described above, to the rigid layer 22a. Thus, the rigid layer 22a, by way of the stitching 26 or bounding, bears at least a portion of the impact force to the backing 24 to facilitate resisting deformation of the backing 24 into the body region R.
As can be appreciated, the front strike face 22, backing 24, and stitching 26 can be modified to influence the reinforcement effect provided by the front strike face 22 to the backing 24.
The rigid layer 22a of the front strike face 22 in this example is a fibrous layer. For example, the fibrous layer includes a layer of fibers 130 that are disposed in a polymer matrix 132. In further examples, the layer of fibers 130 are of aramid fibers, but could alternatively be of other ballistic resistant fibers or non-ballistic fibers. In one further example, the aramid fibers have a denier of approximately 1000-1500. In a further example, the polymer matrix 132 is an acrylic-based polymer. One example acrylic-based polymer is ethylene acrylic polymer. The fibrous layer can be fabricated by laminating the layer of fibers 130 with a layer of the polymer under heat and pressure such that at least a portion of the polymer infiltrates the fibers to form the matrix 132.
The non-rigid fibrous layers 228 of the backing 224 each include a layer of unidirectional fibers 234 disposed in a polymer matrix 236. For example, the fibers 24 are aramid fibers and the matrix 236 is an elastomer. In a further example, such non-rigid fibrous layers 228 of backing 224 could also be used in combination with the front strike face 22 that has the layer of fibers 130 and polymer matrix 132. Similarly, the fabric layers 128 of backing 124 could be used with the front strike face 222 that has the rigid layer 222a that is non-fibrous.
In further examples, to facilitate the reinforcement effect of the front strike face 22/222 on the backing 24/124/224, the front strike face 22/222 and the backing 24/124/224 have a combined weight, and the front strike face 22/222 is 1% to 20% of the combined weight. In further examples, the front strike face 22/222 is 1% to 15% or 1% to 10%, and preferably is 5% to 10%. In a further example, the front strike face 22/222 has a weight of 0.05 pounds per square foot to 0.15 pounds per square foot, and the combined weight is 1.3 pounds per square foot to 1.5 pounds per square foot. For example, higher weight of the front strike face 22/222 relative to the weight of the backing 24/124/224 may provide more reinforcement than needed for the given backing 24/124/224, and lower weight of the front strike face 22/222 relative to the weight of the backing 24/124/224 may not provide enough reinforcement effect for the given backing 24/124/224. Thus, the relative weights are selected within the given range to provide a corresponding resultant reinforcement effect and corresponding resultant limit on impingement into the body region.
Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.
This application claims priority to U.S. Provisional No. 61/936,559, filed Feb. 6, 2014.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US15/14772 | 2/6/2015 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61936559 | Feb 2014 | US |
